Abstract 136: The Incidence of Newly Diagnosed Cancer After a First-Ever Episode of Cerebral Venous Thrombosis: A Registry- and Population-Based Cohort Study

Abstract

Introduction: Active cancer is a known risk factor for cerebral venous thrombosis (CVT), but it is unknown whether CVT is also associated with occult cancer. We evaluated the incidence of newly diagnosed cancer after CVT. Methods: We performed a registry- and population-based cohort study using the Dutch hospital discharge registry. Patients admitted to any Dutch hospital between 1997 and 2020 with a first episode of CVT were identified using ICD-9 and ICD-10 codes. Patients with a history of cancer and patients diagnosed with cancer during admission for the index CVT were excluded. We calculated the cumulative incidence of cancer after CVT with death as a competing risk. Standardized incidence ratios (SIRs) were calculated relative to a control group matched by age, sex, and calendar year with data from the Netherlands Cancer Registry. Results: We identified 2649 patients, 1856 (70%) were women and the median age was 44 (IQR 31-56) years. Cancer was diagnosed in 119 patients during follow-up (median duration 4.7 [IQR 1.9-8.9] years), of which hematologic (24%) and gastrointestinal tract (20%) cancers were the most common. The cumulative incidence of cancer in the overall cohort was 5.9% (95%CI 4.8-7.2) after 10 years. The highest cumulative incidence after 10 years was observed in patients ≥50 years (10.5% [95%CI 7.9-13.4]) and in men (9.9% [95%CI 7.1-13.1]). Patients with CVT had an increased rate of cancer compared to controls during the entire follow-up, but the difference narrowed over time (SIR 3.4 [95%CI 2.4-4.5] at 1 year and 1.4 [1.1-1.7] at 10 years). The rate was increased in both patients younger than 50 (SIR 6.7 [95%CI 4.0-10.6] at 1 year and 1.7 [1.2-2.3] at 10 years) and older than 50 years (SIR 2.4 [95%CI 1.5-3.6] at 1 year and 1.2 [0.96-1.6] at 10 years), as well as in men (SIR 3.6 [95%CI 2.2-5.6] at 1 year and 1.7 [1.2-2.2] at 10 years) and women (SIR 3.2 [95%CI 2.0-4.8] at 1 year and 1.2 [0.9-1.6] at 10 years). Conclusion: Patients with CVT have an increased risk of cancer compared to peers from the general population, regardless of age group or sex. The absolute risk of cancer was highest in older patients and men, while the relative risk was highest in younger patients. These results support the need for further research on screening for occult cancer in patients with CVT.